Supplementary optical instrument.



M. VON ROHR. SUPPLEMEIITAIQY OPTICAL INSTRUMENT.

APPLIGATION FILED JAN. 27, 1909.

Patented Feb. 7, 1911.

UNITED STATES PATENT onrron.

IlVllORI'JZ'Z VON ROI-IR, OF JENA, GERMANY, ASSIGNOR TO THE FIRM 0F CARL ZEISS, 0F

JENA, GERMANY.

SUPPLEMENTARY OPTICAL INSTRUMENT.

To all whom it" may concern:

Be it known that I, MORITZ VON Rona, acitizen of the German Empire, and residing at Garl-Zeiss strasse, Jena, in the Grand Duchy of Saxe-l l eimar, Germany, have in" vented a new and useful Supplementary @ptical Instrument, of which the following is aspecification.

The invention consists in an optical instrument, which is designed for adaptation behind any monocular instrument: magnifier, microscope, endoscope or telescope, and which converts this monocular instrument into a binocular one without materially reducing the objective field of ,view, the monocular instrument together with its sup= plement being hereinafter called the total instrument. The necessary constituent parts of such a binocular supplementary instrument are a dividing prism system and two reproducing lens systems. The dividing prism system divides the system of pencils of parallel rays, which-reproduce the object at a great distance, emerging from the monocular instrument into two partial systems, one for' each eye of the observer. This prism system admits of construction in all those forms which have been employed in the binocular microscope with common objective for dividing thesystem of pencils of convergent rays emerging from the objective and which, as is well known, can be classified into two groups, according as the pencil system is divided physically, that is to say, as regards the individual rays divided, or only geometrically, 2'. 6., as a whole. A transparent and, at the same time, reflecting layer effects the physical division. Instead of being inclosed in a prism system, sucha layer can be also arranged on a glass plate or may even consist of such a plate. Geometrical division should as much as possible take place in the exit pupil of the monocular instrument. It can not only be realized by reflecting but also by refracting prism systems, reflectors of course being capable of taking the place of reflecting prism systems. The two reproducing lens systems preserve to the binocular instrument the objective field of view of the monocular instrument wholly undiminished or but very slightly reduced in size, in that they reproduce the exit pupil of this instrument twice in physical division of the pencil system, or in geometrical division each partial pupil Specification of Letters Patent. Patented Feb, 7, 1911. Application filed January 27, 1909. i 7

Serial No. 474,494.

once, as exit pupils of the total instrument with the same magnification. Since the two images of the object, which the total instrument presents, must lie at a great distance as the image presented by the monocular instrument does, each lens system must allow the pencils entering with parallel rays to emerge again with parallel rays, in other words, it must be a telescopic system. As additional constituent parts of the supplementary instrument reflecting prisms may still be necessary, in order to give the axes of the two partial pencil systems parallel'or weakly diverging directions, provided they have not already received such directions from the dividing prism system, to deflect these axes, forthe purpose of enabling the supplementary instrument to. be adapted to the inter-papillary distance, or to produce additional reflections for rectifying a reverse position of the images,

In employing geometrical division, the distant virtual images of the object, which are visible to the eyesof the observer, represent stereoscopic component images, and

'pseudoscopic effect is to be avoided by arrapging the images according to well known ru es. virtual images are identical and combine in being viewed with the two eyes into an indifferent image. sides of the exit pupils of the total instrument, z; a, on the sides adjacent to one another, or only on the inner side of one of the two exit pupilsa smaller or larger portion be stopped out, the conversion of the images visi e to the eyes into stereoscopic images is also, as is well known, obtained. Physical division has therefore the advantage of being able to realize not only stereoscopic but also indifferent vision.

The idea of converting a monocular micro-' scope by means of a dividing prism system' In physical division the distant If, however, on the inner tion of a dividing prism system, which acts geometrically, with two astronomical telescopes has been already published, accordmg to which these three constituent parts were to be combined with an objective to form a binocular microscope. Accordingly, the invcntion represents an application of the well a plan View of the same parts.

known combination of a dividing prism system with two telescopic systems for the solution of the well known problem of converting a monocular instrument into a binocular one by a supplementary instrument without reducing the objective field of view.

' In the annexed drawing: Figure 1 is anaxial. section through a supplementary instrument fora cystoscope. Fig. 2 is an elevation of the optical parts of a supplementary instrumentfor a magnifien Fig. 3 is Referring to Fig. 1, a Swan cube a with transparent silver layer serves as the dividing prism system. Hence physical division right telescope and finally through a second reflecting prism g. 7 On the casing two main parts are to be distinguished, one part It fixed and one i rotatable. The fixed main part has a tube It", by means of which the supplementary instrument is slipped on the ocular of the monocular instrument. The axis of rotation of the main part i coincides with the axis of the tube h tubes h and i of the two main parts have in the position of the rotatable main part 2' shown in the drawing, in whic the axes of both partial pencil systems res in the same plane, their greatest distance apart. By rotating the main part i this distance canbe reduced-to suit the inter-papillary distance of the observer. On the ocular tubes h and i removable covers 713 and i are placed, each with an aperture "in approximately the formof a semicircle, the center of which lies in the axis of the partial pencil system. The place of the cover on this axis is chosen, so that the exit pupil of the monocular instrument, which'when the supplementary instrument is slipped on, falls near to the entrance surface of the cube a, is reproduced in the plane of the cover aperture. If the covers have the position as shown, in which the apertures lie toward the outside,.stereo-- scopic component images are presented theeyes of the observer. When the covers The ocular scopes (Z have an image-inverting effect,

the images presented to the observer are erect, if the monocular instrument supplies an inverted image, and inversely.

In the example shown in Figs. 2 and 3 geometrical division is made use of. The dividing prism system consists of two reflecting prisms lo and Z. The objective lenses m and the ocular lenses n have here also equal focal length, but in this case, where a monocular instrument 'is supposed to have a large apparent field of view, a collective lens o is arranged in the image field of each telescope. The ocular. prisms 3) have one simple reflecting and one ridge surface each, so that the supplementary instrument in itself provides erect images. If this instrument be attached behind the monocular one, so that the exit pupil 9, Fig. 3., of thelatter falls in the entrance surface of the prisms 7c and Z, then the images 7- of the two parts of q projected by the telescopes lie above the ocular prisms, conveniently accessible to the eye of the observer. Since these exit pupils of the total instrument, as erected images of the parts of the exit pupil of the monocular instrument, turn the dividing lines toward one another, the component images presented to the eye of the observer are stereoscopic. For adapting the distance between the oculars 'to the inter-papillary distance, the two symmetrical halves of the supplementary instrument are capable of beingrotated, as indicated by dotted lines in Fig. 3, about the common entrance axis, if, as shown, the prisms l," and l are suitably truncated. Through this truncation, it is true, a small portion of the rays emerging from the monocular instrument are lost. On that account also the images 1" of the partial pupils appear correspondingly cut down.

I claim A supplementary instrument for converting a monocular instrument into a binocular one, the optical components of this supplementary instrument being arranged 1n a' dividing prism system and two telescopic systems, thc'latte1"systcms being located each behind one of theexit surfaces of the former system.

- MORITZ VON ROHR. Witnesses: PAUL KRiiGER,

FRITZ LANDER. 

